So it's about time to replace your chain. Hopefully you have gotten around 10,000 miles out of it because you have been properly maintaining it every 500 miles...right? Regardless, chains are not something to mess around with if you don't have the right tools and knowledge but if you do and you just need a nice refresher here's the info.
A kinky chain is something to be replaced quickly (or something you hang above a bed). Before you start cutting your current chain make sure that you have the same size chain (eg. 520, 525, 530), the correct amount of links and a good rivet style master link.
Using an angle grinder with a cutting wheel on it, cut through the existing chain making sure to not come in contact with the swingarm.
Make sure to clean all road grime and chain lube collected by the front sprocket and check for any damage to the output shaft seal from debris thrown from the chain.
Move your axle carriers forward to the first quarter of axle travel (unless a certain axle position is specified for optimal wheelbase length, usually necessary for racing purposes. More on this later).
Wrap axle around front and rear sprocket laying both half ends in the center of the rear sprocket. This placement will help determine where the chain needs to be cut and where the master link must be installed. The link that must be cut is the one that only half fits, mark this link with a sharpie and get your grinder out again.
Grind off the top of the rivet and push the rivet through the back side of the chain.
After placing your lubricated o, x, or z-rings on the master link slide it through both open ends of the chain. Place your second set of o, x or z-rings on the outside then your link plate. With a plate-press adapters on your chain tool, press your master link plate down past the tops of the rivets.
Replace the plate-press adapter with the rivet-expanding adapter and the divited adapter on the back side. Tighten the chain tool with rivet-expanding adapter driving into the divit of the master link rivet. Tighten until rivet is expanded and will not pass trough the master link plate but not too hard as to crack the rivet or bind the movement between inner and outer link. Repeat this process on both links and you're good to go.
Celebrate your accomplishments.
Next step is to tighten your chain to the specific spec. For instructions on this either visit, "Basic Maintenance - Chain Adjustment Conventional Swingarm," or "Basic Maintenance - Chain Adjustment - Single Sided Swingarm." To maintain your new chain and make sure it lasts you another 10,000 miles visit, "Basic Maintenance - Chain Clean and Lubrication"